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(No Model.)

E. H. T. LIVEING.

N. PETERS. Pnmrrmhogmgher. wnshmgxw, D. c,

UNITED STATES PATENT GEEICE.

EDWARD H. T. LIVEING, OF QUEEN ANNE STREET, CAVENDISH SQUARE, COUNTY OFMIDDLESEX, ENGLAND, ASSIGNOR TO JAMES JOSEPH HICKS, OF SAME PLACE.

SPIRIT-THERMOMETER.

SPECIFICATION forming part of Letters Patent No. 251,371, dated December27, 1881.

Application tiled August 31, 1881. (No model.) Patented in EnglandSeptember 29,1880.

To all whom it may concern Be it known that I, EDWARD HENRY TOR- LEssELivErNG, a subject of the Queen of Great Britain, residing at Queen AnneStreet, Cavendish Square, in the county of Middlesex, England, haveinvented certain new and useful Improvements in Thermometers, (for whichI have received Letters Patent in England, No. 3,939, dated September29, 1880,) of which the following is a specification.

The invention has for its object improvements in thermometers, andrelates to means whereby greater distinctness in reading and a novel andmore ornamental appearance are obtained than in thermometers of thedescription heretofore in use. For this purpose, instead of supplyingthe tube with mercury or with spirit colored las heretofore, I supply itwith alcohol colored with a body known to chemists as tluorescine,7 withthe addition of a small quantity of some alkali, and I employ incombination with the same a black or other very dark background.

In order that my said invention may be more clearly understood andreadilyT carried into effeet, I will proceed more fully to describe themethod of carrying the same into effect, referring to the accompanyingdrawing, which represents a front view of my improved thermometer.

A is a thermometer-back; B, the tube, having a dark or black background,b and C, the spirit within the tube, colored with uorescine and alkali,so as to present a translucent amber-colored appearance in the bulbportion c and an opaque deep=greencolored appearance to the columnportion c.

The liuorescine (which may be obtained from chemical dealers under thatname) is to be dissolved in the alcohol (the strength of which is notimportant, and methylated spirit of commerce answers well) in theproportion of about one-third of a grain to the uid ounce of spirit.This` proportion can, however, be varied considerably without muchalteration in eect. The liquid thus produced is scarcely at al1fluorescent, but on the addition of a'small quantity of an alkali itbecomes intensely so. For this purpose I employ strong ammonia solution,in the proportion of one drop to the iiuid ounce of spirit; but otheralkalies may be used and the exact proportion is notat all material. Theuid thus obtained is introduced into the thermometer-tubes in the usualmanner, these tubes being preferably made with bulbs of variousornamental forms, such as spiral, helical, or any other form that may befound convenient; but no form is here claimed, the object of such bulbsbeing to display to the best advantage the double color possessed by theduid, which reflects a green light but transmits a yellow light. Tubesthus made and supplied with the colored fluid above described are,according to my invention, to be mounted against a black or other verydark colored scale (with white figures) as a dark background for thefluid; or the dark background may be produced by varnishing the back ofthe tube with black or other very dark colored varnish, or by a band ofblack or other very dark enamel drawn within the glass of the tube or onthe back thereof, in place of the ordinary white enamel used for thispurpose.

If the thermometer be intended for a registering one, the index orneedles must be made of some reect-ing material in order to show withinthe fluorescent fluid. In place of those of black glass commonlyemployed, I find white enamel-glass answers well for this purpose.

Having thus described the nature of my said invention and the mode inwhich I carry the same into effect, I would have it understood that whatI claim isl. An indicator-tube having its contained spirit colored withlluorescine and alkali, as set forth.

2. A thermometer provided with a tube having its contained spiritcolored with fluorescine and alkali, as set forth.

3. A thermometer-tube having a dark background and its contained spiritcolored with liuoreseine and alkali, as and for the purpose set forth.

4. A thermometer constructed with a back, A, tube B, dark background b,and a spirit filling, C, adapted to present a translucent amber-coloredappearance to the bulb portion c and an opaque deep-green-coloredappearance to the column portion c', as set forth.

EDWARD H. T. LIVEING.

Witnesses:

R. W. MAsoN,

8 Hatton Garden. C. M. WHITE,

23 Southampton Buildings.

